This study was conducted to investigate the presence of Epstein-Barr virus (EBV) and human papillomavirus (HPV) and the promoter methylation status of the death-associated protein kinase (DAPK) gene in high-grade intraepithelial lesions. Viral infection was analyzed using polymerase chain reaction (PCR), and promoter methylation status was evaluated using chemical modification by sodium bisulfite followed by PCR. A total of 24 samples were studied. HPV was detected in 16.6%, EBV in 16.6%, and HPV/EBV coinfection in 16.6%. No virus infection was detected in 50% of the samples studied. DAPK promoter methylation was observed in 29.2% of the analyzed samples. There was no significant correlation between DAPK methylation and viral infection. DAPK methylation was detected in 28% of HPV-positive lesions, in 28% of HPV- and EBV-positive lesions, and in 44% (3/7) of the samples without viral infection. There was no observed methylation in samples with isolated EBV infection. In DAPK unmethylated samples, HPV infection was found in 12%, EBV infection in 23%, HPV/EBV coinfection in 12%, and an absence of HPV and EBV infection in 53%. The promoter methylation of the DAPK gene is an important event during carcinogenesis and may have potential clinical application as a marker for the progression and prognosis of cancer.
[Show abstract][Hide abstract] ABSTRACT: Cervical carcinogenesis is a complex problem with papillomavirus widely accepted as a causative agent. Integration of a human papillomavirus (HPV) of the high-risk type into the host cell genome is one of the major contributing factors to cervical malignant transformation. In this study, the correlation of CMV, EBV, HSV-1, HSV-2, HHV-6 and HHV-7 infections with the physical status of the HPV genome in cervical cancer and precancerous cervical lesions was investigated in sixty HPV-16-positive women. Cervical secretion samples were submitted to DNA extraction and analyzed by PCR. HPV-16 DNA was confirmed in genotyping with the reverse hybridization line probe assay. Multiplex PCR with specific primers for the E2/E6 genes was used to assess the viral integration status of HPV-16. Our results show that CMV DNA was more frequently present in samples with mixed forms of HPV-16 than in the episomal form (P < 0.025). Such a correlation was also observed in the case of EBV (P < 0.005). The presence of CMV resulted in a six-fold (OR 6.069; 95% CI 1.91-19.22; P = 0.002), while EBV caused a seven-fold (OR 7.11; 95% CI 1.70-29.67; P = 0.007) increase in the risk of the integrated or mixed HPV-16 genome occurrence. Our data suggest that coinfection with herpesviruses, especially CMV and EBV, may be involved in the integration of the HPV-16 genome and may contribute to the development of cervical cancer.
[Show abstract][Hide abstract] ABSTRACT: Resumen E L CÁNCER DE LA VÍAS AERODIGESTIVAS superiores (CVADS) representa la sexta ma-lignidad más común, con una incidencia anual aproximada de 400.000 personas en el mundo. Aunque los principales factores de riesgo para el CVADS siguen siendo la exposición al tabaco y alcohol, el virus del papiloma humano (VPH) recientemente se ha encontra-do asociado en la etiología del 20 al 25 % de los CVADS, principalmente los ubicados en la bucofaringe. En huma-nos el VPH es causa de cáncer por expresar dos oncopro-teínas virales: E6 y E7. Los estudios han demostrado que E6 y E7 se unen directamente a varias proteínas del hos-pedero, como p53 y pRb, para contribuir a la inestabilidad genética. El tipo de VPH de alto riesgo más asociado con cáncer de las vías aerodigestivas superiores es VPH-16. La positividad a VPH de alto riesgo se asocia a una expresión disminuida de los genes p53 y pRb, la sobreexpresión de p16 y la disminución de la expresión de EGFR, y un patrón de expresión genética diferente respecto a los pacientes con CVADS negativo a VPH de alto riesgo, esto conduce a la conclusión de que se trata de una entidad clínica distinta. Además de las diferencias etiológicos, los cánceres VPH-positivos son clínicamente diferentes en comparación con los cánceres de VPH negativos en relación con la respuesta al tratamiento y la supervivencia, siendo la positividad a VPH un biomarcador pronóstico favorable.. Abstract Upper aero-digestive tract cancer (UADTC) is the sixth most common cancer with an annual incidence of approximately 400,000 worldwide. Although the principal risk factors for UADTC remain tobacco and alcohol use, human papillomavirus (HPV) has recently been found to be etiologically associated with 20 to 25% of UADTC, mostly in the oropharynx. HPV causes human cancers by expressing two viral onco-proteins, E6 and E7. Studies have shown that E6 and E7 can directly bind to multiple host proteins as p53 and pRb, further contributing to genetic instability. The most common high risk-HPV associated with upper aero-digestive tract cancer is HPV-16. High risk-HPV positiv-ity is associated with decreased expression of the p53 and Rb genes, overexpression of p16, decreased expression of EGFR, and a different genetic expression pattern compared with patients with high risk-HPV-negative UADTC, leading to the conclusion that this is a distinct clini-cal entity. In addition to the etiological differences, HPV-positive cancers are clinically distinct when compared with HPV-negative cancers with regard to treatment response and survival outcome, with tumor HPV-positivity being a favorable prognostic biomarker.
[Show abstract][Hide abstract] ABSTRACT: Evaluation of promoter methylation of the death-associated protein kinase (DAPK) gene and HPV and EBV infections in cervical cells from patients with normal cytology and colposcopy.
Twenty women, who had been patients at the Institute of Gynecology of the Federal University of Rio de Janeiro (UFRJ) for routine examinations and who showed normal cytology and colposcopy, were selected for this work. Cervical brushings were used for DNA extraction, and the analysis of methylation patterns of the DAPK gene was done through chemical modification with sodium bisulfite. Analysis of viral infection was done using polymerase chain reaction (PCR).
Of the 20 patients studied, six (30%) presented methylation of the DAPK gene, five (25%) presented infection with EBV and three (15%) presented coinfection with HPV/EBV. Associating methylation with viral infection, we found methylated DAPK in one patient (16%) with EBV, in two patients (33%) with co-infection and in three patients (50%) with no viral infection.
In the present study, we verified, for the first time, the methylation pattern of the DAPK gene in cervical smears from patients with normal cytology and colposcopy. The results also showed the presence of viral infections in these patients. EBV infection, irrespective of whether associated with HPV or not, may contribute to cervical carcinogenesis as a cofactor. Methylation of the DAPK gene is associated with cell transformation, suggesting that DAPK methylation might be an important marker for the development of cervical epithelial neoplasias.
Archives of Gynecology and Obstetrics 12/2007; 277(6):505-9. DOI:10.1007/s00404-007-0511-5 · 1.36 Impact Factor
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